http://www.ck12.org Chapter 3. Chemical Interactions
inhale the radioactive element polonium-210. It undergoes alpha decay in the lungs. Over time, exposure to alpha
particles may cause lung cancer.
Summary
- Alpha decay is one of three types of nuclear decay in which unstable nuclei emit energy with or without a
particle of matter. - In alpha decay, energy and an alpha particle are emitted by a nucleus that is unstable because it has too many
protons. An alpha particle consists of two protons and two neutrons, so it is actually a helium nucleus. - Alpha decay is represented by a nuclear equation. The equation is balanced if the total numbers of protons
and neutrons are the same on both sides of the arrow. - All radioactive decay is dangerous to living things, but alpha decay is the least dangerous.
Vocabulary
- alpha decay: Type of radioactive decay in which an unstable atomic nucleus emits an alpha particle (two
protons plus two neutrons) and energy.
Explore More
At the following URL, read the article and watch the video about alpha decay. Then answer the questions below.
http://teachnuclear.ca/contents/cna_radiation/nuclear-decay/alpha_decay/
- When were alpha particles discovered, and who discovered them?
- Write the nuclear equation for the alpha decay of seaborgium-263. What element is produced in this nuclear
reaction? How many neutrons does it have? - Explain how to use the periodic table to identify the element produced when a given radioactive element
undergoes alpha decay. - What are alpha emitters? Give some examples.
Review
- What is alpha decay?
- Explain why alpha decay occurs.
- If a radioactive element with 85 protons undergoes alpha decay, how many protons will there be in the new
element that forms as the product of the reaction? What element is it? - Fill in the missing subscript and superscript to balance the following nuclear equation. Make sure your
equation is balanced.
222
? Ra→
?
86 Pb +
4
2 He + Energy